Hydraulic pump or motor



Aug'. 4, 1942 t UNITED vsTATEsQ PATENT OFFICE f mimmo rum oniroroa Warren B. Tucker, Dayton, Ohio, assignor to The Hydraulic Development corp. me., wu-

mington, Del., a corporation of Delaware Application May 20, 1940, Serial No. 338,122

s claims. (cl. s- 1an This invention relates to hydraulic pumps or motors, and in particular to a hydraulic pump having a plurality of reciprocating pistons in which one or more pistons perform a suction stroke, while simultaneously, one or more pistons stroke performing piston so as to aid the latter in carrying out its suction stroke.

Another object of the invention is to a hydraulic pump with a plurality of asynchronicaily operating pisons in which at least one of the pistons carries out a pressure stroke, while another piston performs a suction stroke, and in which a portion of the fluid pressure created by a pressure stroke performing piston is conveyed to a suction stroke performing piston for aiding the movement thereof.

Another object is to provide a hydraulic pump or motor having radial pistons reciprocable in a radially bored primary rotor in which at least one pressure stroke performing piston supplies pressure fluid to at least one suction stroke performing piston, to continuously urge the latter upwardly.

Still another object of the invention consists in providing a hydraulic pump or motor of the radial piston type, in which the radial pistons reciproca in a radially bored primary rotor, and

I `engage with their outer ends, recesses in a secondary rotor, and in which the suction stroke performing pistons are continuously held in engagement with said secondary rotor by pressure uid created by a pressure stroke performing piston.

provide A still furtherobject of the invention consists in providing a hydraulic pump, as set forth in the preceding paragraphs, which is simple in construction, cheap in manufacture, and reliable in Referring to the drawings in detail, the pump shown in thedrawings and generally designated III is of the variable radial piston type. and comprises the casing halves il and i2, these being held together in any convenient manner, for instance, by the machine screws I3. The casing half i2 is provided with a projecting portion i4 having a bore I5 which serves for supporting the pintle IB. The projecting portion i4 is provided lwith a threadedpassage Il serving as one port,

for instance, outlet port and connected to the pipe i3.

A similar threaded passage i3 connects the opposite side of the projecting portion I4 with the pipe 23. The passages i1 and I3 lead inwardly s o as to communicate withl the ducts 2| and 22 respectively, leading to the passages 23 and 24 of the pintle I5. The passages 23 and 24 lead to the transverse ducts 25,and 26 opening into the cutaway-portion 2l and 23 near the mid-portion of the pintle; By this means fluid is conducted to and from the cylinders of the pump, as hereinafter explained.

Immediately adjacent the cut-away portions 21 and 23, the pintle IB is provided with an enlarged portion 23. Immediately beyond the latter is a portion 30 which is substantially of the same diameter as the pintle portion 3|, supported in the end projecting portion I4 of the casing half l2. The pintle terminates on its righthand end in a threaded portion 32. Surrounding the pintle portions 3| and 32 are the inner races 33 and 34 of tapered roller bearings. 35 and 35. 'I'he outer races 31 and 33 are mounted in depressions 33 and 40 in the opposite ends of a cylinder barrel or primary rotor 4I. The latter, at its central portion, closely surrounds the enlarged pintle portion 23, and is provided with radial cylinder bores 42 communicating with the cut-away portions 21 and 28 of the pintle I6 and having pistons 43 reciprocable therein.

The pistons, as shown in the drawings, are provided with rounded outer ends 44 adapted to engage the guide ring 45 and to move relative thereto. However, if desired, the rounded ends 44 may be shaped in any other desired manner to reduce the friction between the piston ends 44 and the guide ring 45 to a minimum. To this end, for instance, balls supported by the pistons construction shown in the drawings, the relative the rollers 58. These, in turn, engage the inner surface 5| of the shift ring 52, which latter surface has an outer bearing race. The rollers 58 are maintained in position by retaining rings 58 resting in the recesses in the shift ring 52, and having annular grooves 55 engaging the corresponding projections58 on the ends ofthe rollers 58. At the top and bottom thereof, the shift ring 52 is provided with flattened portions 51 and 58 of thefcasing half |2. At the opposite ends of its horizontal diameter the shiftring 52 is provided with flattened portions 58 and 88. The flattened portion 58 is engaged by a coil spring 8| mounted in a boss 82 having a threaded bore 88 closed by a threaded adjusting plug 84.

By varying the position of the plug 84 in the threaded bore 88, the tension of the spring may be varied. -The flattened portion 88, however, is engaged by one end of a pilot piston 85 reciprocable in a cylinder bore 88 in a boss 81 of the casing half I2. 'I'he cylinder bore 88 is provided with a threaded outlet port 88 in which is se:- V cured the end of the pilot line 88 connected with' the pressure outlet side of the pump.. In this way, a predetermined pressure in the pressure outlet side oi the pump will cause the pilot 'piston` engages anti-friction bearing elements such as casing half I2. After this adjustment is made, the lock washer 15 may be bent to lock the nut 18 in the position of adjustment. The casing half I| of the pump I8 is provided with a recess 11 in which is mounted the outer race 18 of a ball bearing 18, the inner race 88 of which is mounted upon the enlargement v8| of the drive shaft 82. The drive shaft 82 is provided with a further enlarged portion 88 which is secured to the cylinder barrel 4| by meansof the screws 84 (Figure 1).

'Ihe cylinder barrel 4I has provided therein a plurality of radial bores 85 closed at their outer ends by a washer 88 pressed against a shoulder 81 by threaded plugs 88. The lower ends of the radial bores 85 communicate with an annular groove 88 which in turncommunicates with bores 88 and 8|, respectively provided in nuts 82 and 88 which are threaded into the pintle portion 28. The pintle portion has in alignment with the bores 88 and 8| of the nuts 82 and 88, the bores 84 and 85 of somewhat larger diameter which respectively house a ball 8 8 and 81 pressed against valve seats 88 and 88 by means of a spring |88 and |8|, thereby preventing communication between the bore 84 and the passage 28 and between the bore 85 and passage 24.

The thrust of the spring |88 and |8| is such as to allow the balls 88 and 81 respectively to recede from their respective valve seat when a prej determined pressure is established in the pasv sages 28 and 24. The radial bores 85 communicate with transverse bores |82, one end of which is closed by a plug |88 while'the other end communicates-with an annular recess |84 in the pistonsA 48. Communicating with the recess |84 in i each piston 48 is a transverse bore |85 leading j tofanv axial bore |88 in the respective piston 48.

-ss to move toward the left iwan regardftoi Figure 2), thereby shifting the shift ring 52,'

toward neutral position.

The threaded portion 82 at the inner end of and extends into the pintle portion 88. A key within the key way 12 forms part of the lock washer 1I and prevents it from rotating, and at the same time, an ear extending from the lock washer 1| engages one of the slots in the-edge of the nut 18 and prevents the rotation of the latter.

'I'he opposite outer end of the pintle I8 is similarly provided with a threaded portion. 18 having `a key way 14 therein. A key within the key way 14 likewise forms a part of the lock washer 15 and prevents the lock washer from turning, whereas an ear on the lock washer engages one of the slots in the edge of the nut,18 Vupon the threaded portion 18 and prevents the rotation of the nut. By turning the nut 18 with the lock washer 15 released, the pintle I8 may be made to move longitudinally to adjust the clearances of the tapered roller bearings 85 and 86.

When, for example, the pintle I8 is moved to the left, the nut 18 and its lock washer 1| push the inner race 88 against the rollers 851, and .the latter push the outer race 81 and the cylinder barrel 4| to the left. This action closes the clearances existing between the rollers 88 and the inner and outer bearing recesses 84, 88, the inner bearing recess being kept from moving by its engagement with the inner wall of the flhef-bore -1 88 forming a booster cylinder, is enfga'g'edvby a plunger |81 rigidly connected with V .the-barrel 4| by means of the arm |88, so that pressure liquid introduced into the booster cylin- `-riery |88 causes the respective piston 48 to engage thefgllide ring 45.

' Operation -the operation of the pump assembly, shown linjfthe'- drawings, power is applied to the drive vshaft 82 from any convenient source, such as an electric motor. The rotation of the drive shaft 82 'l causes the rotation of the barrel or primary rotor 4I. vWhen the shift ring 52 is moved laterally, lfon-instance, toward the right, as shown in Figurej2,vso that its axis is eccentric to that of the pintle I8, the pistons 48 are reciprocated in the cylinder bores 42 vwhen the cylinder barrel or y primary rotor 4| rotates. As the pistons 48 reciprocate, their rounded ends 44 engage the guide ring 45 and move in an annular path while approaching the -center of the pump during onehalf of the revolution, and receding during the other half. During this rotative movement of the pistons, only a slight movement thereof relative to the guide ring 45 is effected in correspondence to the eccentricity between the guide ring 45 and the primary rotor 4I.

While during rotation of the cylinder barrel or fact that fiuid pressure from those pistons 42 performing a pressure stroke is conveyed into the booster cylinders III of those pistons 4I performing a suction stroke, so that the pressure fluid in the said booster cylinders causes the suction stroke performing pistons to engage with the adjacent surface of the guide ring 4l. Bupposing, for instance, that the pressure stroke performing pistons deliver pressure fluid into the passageway 2l, then pressure in the passageway 24 lifts the ball 81 from its valve seat l! so that pressure fluid passes from the passageway 2l into the bore 95, and from there through the bore li into the annular groove 89. From here, pressure fluid passes through the radial bores Il and the transverse bores |02 into the annular recess I A of those pistons which perform a suction stroke, and hence into the respective booster cylinders |08. In this way, all pistons 43 are constantly maintained in engagement with the guide ring I5.

The reciprocation of the pistons 43, in this manner, causes pressure fluid to be discharged from the outlet pipe and thus fluid passes onward to the machinery or circuit which is intended to be operated, while fluid from a fluid source, such as a fluid tank, enters the pump through the inlet pipe I8 and the passageway 2l. From here it passes to the suction stroke performing pistons. If the fluid pressure exceeds a predetermined value, the fluid reaching the pilot cylinder bore 86 through the branch line Il acts upon the pilot piston 85 urging it to the left (with regard to Figure 2) and with it the shift ring 52, thereby overcoming the thrust of the coil spring BI. This action tends to move the shift ring toward its neutral position so as to reduce the discharge of the pump.

It will be understood that I desire to comprehend within my invention/such modifications as my come within the claims and scope of the invention.

Having thus fully described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A fluid pump or motor comprising an inlet conduit, an outlet conduit, a plurality of cylinder bores, pistons reciprocably mounted in said cylinder bores and adapted alternately to take in fluid through said inlet conduit and to press fluid into said outlet conduit, booster cylinders f provided in said pistons and cooperating with correspondingly shaped booster plungers, and means adapted automatically to connect said outlet conduit with the booster cylinder of a suction stroke performing piston to aid the latter in its suction stroke.

2. A fluid pump or motor comprising an inlet conduit, an outlet conduit, a plurality of main cylinders each having reciprocably mounted therein a main piston adapted alternately lto take in fluid from said inlet conduit and to press fluid into said outlet conduit, an auxiliary cylinder provided in each piston and cooperating with an auxiliary piston stationary with regard to the respective main cylinder, and means responsive to the supply of pressure fluid to said outlet conduit by a. pressure stroke performing main piston to connect said outlet conduit with the auxiliary cylinder of each piston performing a suction stroke to aid the same in its suction stroke.

3. A fluid pump or motor comprising an inlet conduit, an outlet conduit, a plurality of main cylinders, pistons reciprocably mounted in said fluid from said inlet conduit and to press fluid into said outlet conduit, each piston being provided with an auxiliary cylinder having tele-- scoped therein a plunger maintaining stationary with respect to the main cylinders, and ,valve means responsive to the creation of uuid pressure by a pressure stroke performing piston to connect said outlet conduit Awith the auxiliary cylinder of each suction stroke performing piston to aid the same in its suction stroke.

4. A fluid pressure pump or motor comprising a rotor with radial cylinder bores, pistons reciprocable in said bores and adapted alternately to perform a suction stroke and a pressure stroke, a control member surrounding said rotor and shiftable into eccentricity with respect to said rotor, said control member including a guiding means for said pistons, each piston having formed therein an auxiliary cylinder with a plunger telescoped in said auxiliary cylinders, conduit means adapted to connect the pressure side of each pressure stroke performing piston with the auxiliary cylinder of each suction stroke performing piston, and valve means responsive to a pressiue stroke of said pistons for effecting communication between an auxiliary cylinder and the kpressure side of a pressure stroke performing piston to cause each suction stroke performing piston to remain in contact with said guiding means.

5. A fluid pressure pump or motor comprising a cylinder barrel having cylinder bores, pistons reciprocably mounted therein and adapted alternately to perform a suction stroke and a pressure stroke, each piston being provided with an auxiliary cylinder, guiding means surrounding said cylinder barrel and adapted to be shifted into eccentricity with respect to said cylinder barrel, said guiding means being engageable by said pistons, a stationary but adiustable pintle mounted within said cylinder barrel and rotatably carrying said cylinder barrel, a plurality of plungers carried by said cylinder barrel, one plunger being associated with the auxiliary cylinder of each piston, and conduit means provided in said cylinder barrel and adapted to effect communication between the pressure side of each pressure stroke performing piston and the auxiliary cylinder of each suction stroke performing piston.

6. A fluid pressure pump or motor comprising a casing, a pintle therein, a cylinder barrel rotatable on said pintle, main pistons reciprocable radially in said cylinder barrel and adapted alternately to perform a pressure stroke and a suction stroke, each main piston having an outwardly disposed head and forming one part of an auxiliary cylinder piston assembly, the other oooperating part of which is carried by said cylinder barrel, guiding means shiftable selectively into or out of concentricity with said barrel and directly engaging said piston heads, and means adapted in response to a pressure stroke of said main pistons to supply pressure fluid from the pressure side of each pressure stroke performing main piston to the auxiliary cylinder piston assembly of each suction stroke performing main piston to maintain the latter in engagement with the adjacent surface of said guiding means.

main cylinders and adapted alternately to take in 7. A fluid pressure pump or motor comprising, a pintle, a cylinder barrel rotatably supported on said pintle, pistons reciprocable radially in said barrel and adapted alternately to perform a suction stroke and a pressure stroke, each piston having an auxiliary cylinder with a plunger telescoped therein, and stationary with respect to said cylinder barrel, inlet conduit `means adapted to communicate with the suction side of each piston, outlet conduit means adapted to communicate with the pressure side of each piston. and valve means responsive to the pressure stroke oi' said pistons for establishing hydraulic communication between said outlet conduit means and the auxiliary cylinder of each suction stroke performing piston to admit pressure fluid to the latter for aiding the same in its suction stroke.

8. In a duid pressure pump or motor having a rotor with a plurality of radially arranged main cylinders and a ring member surrounding said rotor and movable selectively from 'a position concentric to said rotor to a position eccentric thereto or vice versa, a plurality of main pistons respectively reciprocable in said main cylinders and adapted alternately to perform a suction stroke and a pressure stroke while being guided by said ring member, each of said main pistons comprising one part of an auxiliary cylinder piston assembly, the cooperating other part of which is carried by said rotor and stationary with respect thereto, conduit means respectively associated with said auxiliary cylinder piston assemblies for admitting pressure iluid into andreleasing pressure fluid from said auxiliary cylinder piston assemblies, and means forA establishing communication between a main cylinder of a, pressure stroke performing main piston and an auxiliary cylinder piston assembly pertaining to a suction stroke performing main piston to maintain the latter in-engagement with said ring member.

WARREN R. TUCKER. 

